Dragline buckets or bucket assemblies typically comprise a bucket with a base or bottom wall, two opposed side walls or side wall portions extending upwardly from the base to define a front opening and a rear wall also extending upwards from the base. A plurality of forward projecting teeth generally extends from a lip at the front of the base for the purpose of digging. Some buckets have an arch over the front opening for the purpose of connecting a dump cable thereto for tilting the bucket. Typically, trunnions or some other suitable connecting means extend outwards from the side walls of the bucket behind the center of gravity for the connection of hoist chains which extend upwards and inwards to a point above the bucket where they connect to a lifting cable via various rigging components.
Generally, a spreader bar extends between the hoist chains a short distance above the top of the bucket so as to hold the chains away from the outer faces of the side walls against the force applied to the chain by the lifting cable thereby inhibiting engagement of the chains with the side walls. In some cases, each hoist chain has a lower part extending from the trunnion to the spreader bar and an upper part extending from the spreader bar to the lifting cable. The lower part of each hoist chain is typically referred to as the lower hoist chain and the upper part, the upper hoist chain. In some cases the upper and lower parts are separate chains.
In use, dragline buckets are often dropped from significant heights which can result in the spreader bar hitting the upper edge of the bucket and damaging the spreader bar. Sometimes, in the normal course of operation the spreader bar can drop a short distance onto the upper edge of the bucket and still cause damage. Further, dragline buckets have been increasing in size in recent years putting greater loads on the spreader bars with greater widths requiring longer spreader bars. The failure of a spreader bar results in significant downtime resulting in loss of production.